Britain English and American English are the two most influential ones that we study as the second language. They have many differences between them. Most people like to learn American English, because America is an advanced science-technical country. But it’s hard to master American English. If we want to study it well, we must know something about it, Here I give a superficial approach to its development、category、formation and characteristics of its vocabulary. Britain English and American English are the two most influential ones that we study as the second language. They have many differences between them. Most people like to learn American English, because America is an advanced science-technical country. But it’s hard to master American If you want to study it well, we must know something about it, Here I give a superficial approach to its development, category, formation and characteristics of its vocabulary.